Many lakes in the upper Mid-west are used for summer recreation activities like swimming, boating, fishing and sunning. Docks on these lakes help facilitate these summer activities. However, many (if not most) of these lakes are covered by ice in the winter. This ice can damage a dock, so most dock owners remove their docks in the fall and reinstall their docks the next spring/early summer.
For ease of installation, most of these removable docks are modular—having vertical support legs that support frame members upon which sections of docking material rest. Modular docks using aluminum support legs and aluminum frames are well known and have been in use for years. Aluminum provides many advantages over other docking materials such as wood and steel. Aluminum does not corrode like steel, nor does it rot like wood.
Providing a clamping system so the support legs can properly support the frame members has been difficult, however. Most existing docks clamp the frame to a tubular support leg by inserting the tubular support leg through a somewhat larger cast aluminum tube that is fixedly attached to the frame member. A tightened set screw prevents vertical movement of the tubular support frame leg. Examples of such systems are disclosed in U.S. Pat. Nos. 2,571,337, 3,345,825, and 4,074,537.
These “set screw” systems did not provide an abundance of frictional force. Therefore, if one wanted a dock to hold a heavy load one had to provide numerous support legs. In an attempt to overcome this limitation, dock owners began to use cast aluminum clamping system consisting of two cast aluminum c-clamp sections held together by a pair of bolts and nuts. Such a system is shown in FIG. 10. To assembly such a system, as shown in FIG. 10, one would put the tubular support leg into the open “c” section of the first cast aluminum c-clamp section, which is fixedly attached to the frame member. The second cast aluminum c-clamp section would then be placed on the opposite side of the tubular support leg from the first cast aluminum c-clamp section and the two cast aluminum c-clamp sections would be tightened onto the tubular support leg using a pair of bolts and nuts.
Cast aluminum clamping systems of this sort, while providing more support than the “set screw” clamping systems, still do not provide an abundance of vertical support since the cast aluminum c-clamp sections do not grip the support leg with the entire interior face of the “c” sections—they only grip with the upper and lower portions of the “c” sections as shown in FIGS. 10 and 11. Also, cast aluminum is brittle and can easily crack if a dock owner tightens the nuts and bolts too much—an event that commonly occurs when a dock owner wants to provide more frictional vertical support from the clamping system. Finally, these cast aluminum clamping systems are difficult to install. An installer must use one hand to hold the frame member and the other hand to install the second c-clamp section and tighten the nuts and bolts. Often it takes at least two people to install such a cast-aluminum clamping system. Such cast aluminum clamping systems (as well as the “set screw” clamping systems) used in a modular decking system do not provide a high degree of torsional stability (i.e. there is “play” in the system). Such “play” makes a modular deck system less secure (both in actuality as well as in feeling) when bearing loads.